fix paging opportunity calculation in RRC and add respective unit test

srsenb/hdr/stack/rrc/rrc_paging.h

@@ -32,7 +32,7 @@ public:
     T(default_paging_cycle_),
     Nb(static_cast<uint32_t>((float)T * nb_)),
     N(std::min(T, Nb)),
-    Ns(std::max(1U, Nb)),
+    Ns(std::max(1U, static_cast<uint32_t>(nb_))),
     logger(srslog::fetch_basic_logger("RRC"))
   {
     for (subframe_info& sf_obj : sf_pending_pcch) {

srsenb/test/rrc/CMakeLists.txt

@@ -18,6 +18,10 @@ target_link_libraries(erab_setup_test test_helpers ${LIBCONFIGPP_LIBRARIES} ${AT
 add_executable(rrc_mobility_test rrc_mobility_test.cc)
 target_link_libraries(rrc_mobility_test srsran_asn1 test_helpers ${ATOMIC_LIBS})
 
+add_executable(rrc_paging_test rrc_paging_test.cc)
+target_link_libraries(rrc_paging_test srsran_asn1 test_helpers)
+
 add_test(rrc_mobility_test rrc_mobility_test -i ${CMAKE_CURRENT_SOURCE_DIR}/../..)
 add_test(erab_setup_test erab_setup_test -i ${CMAKE_CURRENT_SOURCE_DIR}/../..)
 add_test(rrc_meascfg_test rrc_meascfg_test -i ${CMAKE_CURRENT_SOURCE_DIR}/../..)
+add_test(rrc_paging_test rrc_paging_test)

srsenb/test/rrc/rrc_paging_test.cc

@@ -0,0 +1,48 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2021 Software Radio Systems Limited
+ *
+ * By using this file, you agree to the terms and conditions set
+ * forth in the LICENSE file which can be found at the top level of
+ * the distribution.
+ *
+ */
+
+#include "srsenb/hdr/stack/rrc/rrc_paging.h"
+#include "srsran/common/test_common.h"
+
+using namespace srsenb;
+
+void test_paging()
+{
+  unsigned       paging_cycle = 32;
+  float          nb           = 1;
+  paging_manager pcch_manager{paging_cycle, nb};
+
+  unsigned ue_id    = 4780;
+  unsigned mmec     = 10;
+  uint8_t  m_tmsi[] = {0x64, 0x04, 0x00, 0x02};
+
+  pcch_manager.add_tmsi_paging(ue_id, mmec, m_tmsi);
+
+  // \remark: See TS 36.304, section 7.1.
+  unsigned N   = std::min(paging_cycle, (unsigned)std::round(nb * paging_cycle));
+  unsigned Ns  = std::max(1, (int)nb);
+  unsigned i_s = (ue_id / N) % Ns;
+  TESTASSERT_EQ(0, i_s);
+  tti_point t{0};
+  for (unsigned count = 0; count < 1024 * 10; ++count, ++t) {
+    if (pcch_manager.pending_pcch_bytes(t) > 0) {
+      fmt::print("[{}]\n", t);
+      TESTASSERT_EQ((paging_cycle / N) * (ue_id % N), (t.sfn() % paging_cycle));
+      TESTASSERT_EQ(9, t.sf_idx()); // PO when i_s == 0.
+    }
+  }
+}
+
+int main()
+{
+  test_paging();
+}